R1100GS hack build by PaulRS

After riding my old R69S/EML for nearly 30 years, it was time to build something more modern to cope with todays traffic whilst commuting 40 miles of highway.

So I bought myself an elderly R1100GS from a friend for a friendly sum, with some known faults.
The box jumped second gear, so a M97 box was found, the engine was a bit tired, so a R1150RT engine was fitted and that was fitted with 'Lenny's sprockets'.
That would make a great tug for the 'new' hack.

So, after some research a plan was made.

I wanted a 15" rear wheel from a Smart car, so an adapter was made.



Here the adapter, with a rear disk and caliper from a K1100 already fitted.



Adapter fitted.



View from the right, fits nicely



View from the rear, 165/65R15 tire mounted on a 5,5" rim, with the mount for the exhaust modded, it fits, just.
The wheel is about 20 mm offset to the left.



That's the rear done.
A dummy shock was made for the real shock to be serviced, revalved and a stiffer spring fitted.



Smart wheels use bolts with a rounded taper, but because I am using studs iso the hem bolts, the bolts where drilled and cut in a lathe to leave me with the tapers only, to be fastened with self locking nuts.



The rear done, next is the front.
For lighter steering a trail reducer was made, mated to a fork bridge off a R-RT, to get the trail at approx 60 mm and lower the front by the same amount as the back.



Here you can see the difference between the R-GS and R-RT bridge,



One thing that is a thing to keep an eye on, is due to fitting the trail reducer, the front fork is angled forward, putting an extra load on the isolators in the upper triple three, where the legs go.
I have yet to hear them fail, but still.



So this is where I'm at for the moment.
Bike on the centerstand with 2 pieces of 2x3 under the wheels to get it level.



I have used my max allowed pictures in one message, so I'll continu in a next.

Stay tuned.

Paul.

great start!!

smaller posts will allow folks to ask specific questions without a huge quote.

Continued from the previous post.

Some pictures of the mock-up.
I think it looks rather smart.







I even think that bike is smiling at me.

Next step is to build a subframe, steel is ordered and to be delivered sometime next week.
但首先,培根, bacon is good.



As I said, stay tuned for the next instalment.

Paul.

No need to quote, just hit the 'post reply' button and fire away.
Or quote the whole post, delete what is irrelevant and leave whatever is relevant for your question.

Paul.

Great start!

A lot of work to make those tapers for the wheel studs. Too bad you can't find those tapers in a store.

On the exhaust, looks like you are still using a 1100GS exhaust? With an 1150RT engine, I won't suggest you change to an 1150RT exhaust, but I will suggest you consider an 1150GS exhaust with a straight pipe connecting it to the header pipe. I did this on my 1100 and it gave me the flexibility to go as wide as I wanted on my tire. I was able to fit a 205 tire without a problem. In the first pic below, you can see the simple bracket I made to hang the can from the passenger peg. In the 2nd pic, you can see how much clearance there is -- the tire in that pic is a 170. The 3rd pic shows the pieces.





Not trying to complicate your life, but I think the way you have it now you have to remove the exhaust to change a flat tire? Food for thought.

Good catch, Drone. When I first had my Ural on the road, I thought hard-mounting an ammo box to the left side where a pannier would go was a great idea for holding a fuse block and other wiring. Then I got a flat pusher and had to jack the rear up so high just to get the tire off that I got a nosebleed. Then the flippin' jack collapsed.


The box came off as soon as I got home.

Fabbing those tapers out of the bolts is one of the easier parts of this build.
Lathe, drill, cut twice (3x).
As those are not straight tapers, but rounded, or radiuses tapers, you need to find the exact radius and that requires time on the internet, if you can find the oem specs, that is.

As for the exhaust, 1150RT/RS uses the same exhaust as the 1100 variant, the GS is a different shape, same volume.
Only difference between GS and RT/RS are the headers, RT/RS have same length, where the GS has not, but the search is on for those.
I like my exhaust quit and legal, the law is strict around these parts of the globe, especially in Germany, no 'E' number on the muffler and LEO will deem the system illegal and ends your ride. Simpel as that.

Clearance is not an issue, the wheel slides in and out without touching the exhaust.
Looks a bit odd due to the angle of the pic.

Paul.

In for the ride.

Great you started this build topic.
My K75 was giving signs of old age this summer. I have bought a '96 R1100RS which i'm going to convert. I'm going to re use my rear wheel adapter but with the wider Smart rear wheel rim. I'm going to make the same trail reducer you did.
I'm anxious how you are going to make the subframe. I'm going for a lower frame in Tripteq style but with balls to adapt the tulip claws of the Moturist. Somehow i'm going to connect the subframe over the footpeg attachment to the engine frame connection to function as a hard part. The rear upper will probably somewhere clamped to the duo hangers/subframe. the Aussies proved it works. But the forward upper still bothers me. I would like to use the frame/telelever mounting as Tripteq does but i think it is too far rearward to be stable. My other idea is to replace four imbus bolts of the front engine cover with longer ones to attach a strip across the engine. Maybe a combination of both.
As i said, i'm very curious how you are going to tackle this forward upper mounting.
And to keep it in style, if i run into an GS with a written off engine i might replace the upper half of the bike.

@PaulRSnice work, looking great!

For the subframe, I looked at several options.
Tripteq is too light for my liking, what EZS makes is too heavy.
And then there are some examples found here on this very site.

I will end up with a rectangular frame out of 30 x 30 x 3, with 6 mm brackets.
Attached to the lower, front hole on the engine, the mounts for the stand and at the rear up to the hard parts fitted on the gearbox.
Something along this lines;



I can also incorporate the mounting point for the reaction arm for the final drive.
Balls will be welded/bolted below the footstep and at the front of the engine.

The rear upper mount will be up in the triangle of the rear subframe, as close as possible to the bracket where the rear shock mounts.

For the front upper mount, there's the 2 M10 bolts going into the engine, I know of 3 hacks which uses those, one hack is ridden hard, very hard, and loaded with a 60-70 kg dog in the chair, gear and the wife on the back.
It holds nicely.



Two longer bolts, bushings and a bracket, job done.
I will have a look if I can get the hole above in with that bracket, but there's the front swingarm, I need to look how that works out.

But first things first, get the lower subframe made, and the car's frame fitted,

Paul.

That is convenient, having an old engine and gearbox at hand.
I think a variation of Tripteq is solid enough. Ruud, nickname Viking, a member of MC Alzheimer has had an R1100GS with an Ural tub and an even simpler frame. He went to the Kristall rally and several other rally's with that combo without any problem.
Your picture with the piece of wood explains a lot. I have collected a lot of pictures but none show the actual height of the frame/tube. Now it is clear thet the lwr fwd M12 bolt comes on top of the tube.
Do you have pictures of the fwd upper mounting using the two M10 bolts? I have never seen a sidecar using these. It sounds very sensible, but why is it so rarely used? Does it interfere with the exhaust? I remember having seen an American solution using two M6-es of the front cover and one of the M10 bolts but that was years ago.
My K75 combo currently uses the single M10 engine bolt as fwd upper mount. I have done two rounds of Belgium/France/Germany with it and it holds up. Using the Two M10 bolts of the R1100 engine casing with a bracket must do the trick.

inspiration:

No pic.
I once found a pic from some French guy, but I didn't save it, nor can I find it now.
But it stuck in my head.

That pic you show is about it, a plate bolted on, with a tab for the strut, that tab should be as close to those bolts as possible to avoid bending forces, but you can incorporate the 2 M6 bolts from the front cover.
The strut will go below the header to the car's frame, no problems there.

This Ruud/Viking guy, do I know him, sounds familiar?

Paul.

You inspired me . I've started this afternoon with the RS. I will start a new topic not further polluting yours. I think the fwd upper is doable as you suggest it. It will be very tight around the exhaust. I will make the base plate but without a tab for the strut. If you move the sidecar a bit wider the strut will interfere with the exhausts, it comes very close. I will try to make an adjustable tab or weld the tab on if everything is aligned.
I think you should have met Ruud somewhere. He is also from Noord-Holland (maybe Alphen a/d R). A bit younger than we are, blond with a pony tail. He sold his R1100GS last year.

So today's plans where blown and washed away due to high winds and the occasional shower, I ended up with some shed time.

I still wasn't happy with the clearance between the rear tyre and the exhaust.
切割和重焊后尾部安装后,the muffler moved away from the tyre about 10 mm, but moving the rear wheel up and down the travel of the shock, it still was too close for comfort.

静态检查免费房间是完全不同的thing than with the bike on the move, there is some flex in everything, so some more room was needed.

So off with the pipe, and out came an old pillow and some hammers.
With the pipe on the pillow, I slowly hammered the wheel side of said pipe, tap, tap, tap, until I got the whole side flattened.
Easy goes a long way, the result is about 15 mm clearance over the whole length of the muffler, without making too much of a mess of things.



Doesn't look too bad, or does it?



Paul.

What a difference a week makes.

Ha, a lot can happen in a week.

I checked the clearance with the bike's ass lifted and got the wheel in and out ok.
But what I didn't check (or I did and forgot) was the clearance whilst moving the wheel up and down it's travel, then it was close enough to slightly rub.

And there will be more things that get overlooked, or forgotten during this build, I ain't 25 anymore.

Paul.

So today I found some time to do some work on this project again.

Last week I made some brackets for the subframe, mounted them to the main stand fixtures and clamped a length of 30x30x3 box on to get a start for the subframe itself.



Then I ground of the existing mounting points, when I first bought this sidecar, it was mounted to a GoldWing, I modded the frame to fit the /2 frame I used for the last 25 jears.

Off comes the front.
I remembered I cut of the old Honda mounting and fitted the /2 mounting by inserting a piece of solid rod to give the tube some support before welding, so gently grinding about 3mm into the tube so not to disturb the old rod.



Next is the rear.



Then some alignment, level front to back, and side to side.
So the chair's frame is shimmed, level and parallel to the box section for the subframe.



The chair's wheel should be vertical.



Final adjustment for toe-in can be made here, the whole wheel's mounting is welded to a slotted plate, which bolts to a plate welded on the chair's frame.



Close up view.



This also shows that 25 years of winter salt takes it's toll on powder coat.

And here we have the front lower ball joint tacked in place.



Next will be the rear lower, then finishing the subframe and complete all the tack welds.

Stay tuned.

Paul.

Have you measured the width with the rh case fitted? Will you still be able to remove the case when the tub is fitted?